Internal combustion engine



FpgvLEcKA INTERNAL COMBUSTION ENGINE Filed July 1, 1931 2 shets-sheet `1.l//////////l Kim.

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April 30, 1935. J. PAVLECKA 1,999,374

' INTERNAL (-OMBUSTION ENGINE med Ju1y 1, 1931 2 sheets-sheet 2 IN VENTOR.

aented i. .t im t t;

.ma ravie@ permit, en.

Application .fully ll, will, erlall No. .'idihll'l tion thereof as apart of an airplane, viz., one so compact as to oder the leastresistancel in night.

it further object is to provide a radial engine for aircraft which willadord utmost ease in assembling and accessibility in service.

important object of my invention is to devise an engine which willembody a starter and an induction impeller in a practical way and thusinsure safety and convenience in starting and high efficiency inoperation.

These and other objects and aims hitherto not materialized are affordedby my engine which, though operating on but established principles ofmechanics and thermodynamics is inherently suitable for aircraftpropulsion by virtue of its structural configuration.

Although the all-round advantages of the radial engine for aircraft havebeen recognized, it isV well known that this type, When installed in anairplane, is inferior to the in-line engine in the matter of airresistance. In order to eliminate this basic drawback of the radialengine I have resorted to a new arrangement of the engine umts.characterized mainly in that all the auxiliary units and all theaccessories are disposed between the engine cylinders and the propeller,which is distinctly unanalogous, if not altogether contrary to thegenerally .known and adopted practice of locating the cylinders directlyadjacent the propeller. Due to the grouping of the engine units in theaforementioned new order the engine cylinders will be distanced from thenose of the aircraft body into a portion thereof having a diameter solarge that the cylinders will be completely or at least from the largestextent enclosed within the streamline contour of said body. The cooling.of an engine so enclosed, if either by air or a liquid, is effectedpreferably by the internal, forced and controllable system of coolingwhich forms subject matter of my Letters Patent No..1,779,186; asdisclosed therein, a stream of air is forced or induced into theaircraft body through the forward end thereof by means of a conoidalimpeller, the air being directed to and around the engine cylinders insaid body, or through a liquid radiator therein, and -then dischargedbehind the engine into the slipstream.

Y Among the novel features embodied in the engine of my invention andhereinfurther referred Al ica-5s) to is the induction system which formssubject matter of my Letters Patent No. 1,889,262.

The above is a broad account of the subject matter ofmy presentinvention to the exclusion of all detail but nevertheless important anddistinct features, all of which will now be described with reference tothe drawings accompanying this specification and forming an integralpart thereof.

lin the drawings,

Fig. l represents av longitudinal cross-section through the whole engineand shows clearly the novel grouping of the units therein as well as allother essential features.

Y Fig. 2 is a transverse cross-section through the engine of Fig. llooking in the direction from the propellerto the cylinders; the topportion of this view is taken on the center line of thevalve tappetsv I5(Fig. l) while the bottom portion is taken at a point slightly ahead asindicated by the letter A in Fig. l.

The individual units in the engine represented in Fig. lmay be identiedas either well-known or as disclosed in the Letters Patent 1,889,262above referred to, all being disposed in relation and in combination toone another and in the whole in a novel and original manner to yield thedenite and useful results contemplated.

The engine has a number of cylinders I2 arranged substantially radiallyon a crankcase which, in this particular embodiment, is shown as made upof two halves'ZI and 23. Thel cylinders I2 comprise each the piston 'I2and the connecting rod 13; the head of the cylinders is shown as being,by way of example, detachable, and the valves II-in case the engine is afourcycle one-as being on the side of the cylinders, the combustionchamber being of the L type. The crankshaft of the engine consists ofthe straight shaft portion I6 which extends through the whole engineassembly and terminates, at the driven extremity, with the crank arm I1and the crank pin I8 to which journalled are the connecting rods 13, andwith the propeller boss 20 at the extremity. On and around the shaft-portion I6 between the cylinders I2 and the -propeller boss 20 aredisposed all the accessories, gear trains and auxiliary units of theengine in approximately the following sequence: the valve mechanismincluding the gears I, 2, 3 and 5, the cam ring 6, the valve tappets I5and the valves Il; the tachometer drive comprising the gears 9 and I0;the oil pump drive gear II and the oil pump Vwhich consists of the gears8l and disposed in pairs on the shafts I2 and I3 in the lowest portionof the engine crankcase adjacent the. oil filter 87.

Forwardly of the valve mechanism above introduced is the centrifugalimpeller 55, and peripherally around it a plurality of induction ducts26 connecting to the cylinders I2. The ducts 26 are fashioned preferablyafter the manner disclosed in my Patent No. 1,889,262 for the inductionsystem above cited, their inlet aperture being, briefly for furtherreference, relatively narrow but angularly greatly extended around theperiphery of the impeller 55 while their exit aperture at the associatedcylinders is approximately circular, conforming to the intake valveport, and the passage between said two apertures is characterized by asubstantially curvilinear formation proceeding outwardly and angularlytoward the associated cylinder in a direction given generally by theresultant of the tangential and the normal velocity components of thedischarge from the impeller I2.

Next to the impeller 55 is the riser 48 which communicates between anoutside carburetor 45 having an intake funnel 41 thereon, and an annularexit channel embracing the shaft I6 and housing a plurality of guidevanes 50l for imparting the charge with an initial angle of whirl; theadmission of the charge is controlled by means of the throttle or chokefiy 49 in the riser 48. In case the engine operates on the Dieselprinciple, then, of course, the carburetor 46 is dispensed with.

Follows a pair of helical gears 53 and 5I representing the accessorydrive, the accessories being either a magneto, a distributor, agenerator or, in a Diesel engine, the fuel supply pump. The gear 53 ison the shaft I6 while its mate 5I is carried on the transverse shaft 52,to which externally coupled is the magneto, distributor, generator orfuel pump 5l.

Adjacent the gears 53 and 5I is the starter which is shown as beingpreferably of the torsion spring type. The essential elements of thestarter include the winding worm 6I in engagement with the w'orm Wheel62, the torsion spring 66 connected at the inner end thereof to saidWorm wheel 62 and to the control drum 63 at the outer end. The drum 63is provided with locking and releasing ratchet teeth 64, and through aclutch of the over-running type entrains the shaft I6 for starting theengine by the spring 66; the clutch is shown as being, for instance, ofthe ball or roller variety, the pellets 6l being inserted between thedriving cylinder 65 which is integral with the drum 63, and the cams 54'on the sleeve 54 secured to the shaft I6.

Forwardly of the starter cylinder 65 is the bearing 10 held axially xedin the cylindrical portion 3I of the end casing 29 as by the snap ring68 on one side and a shoulder on the end cover 3| on the other. The nutII having threaded engagement with the shaft I6 secures the bearingthereon.

'Ihe shaft portion I6 of the crankshaft is supported rotatably, as forexample, in two bearings, 59 and 10, located at the driven and thedriving extremities thereof respectively; overhanging the two bearingsupports are the propeller boss 20 fore, and the crank arm II aft; thelatter carries, diametrically opposite to each other, the crank pin I8and the counterweight I9. The crank pin I8 has a cantilever relation tothe arm I1, there being preferably no arm symmetrical to the arm IIabout the axis of the cylinders I2 and, of course, no ccunterweight orshaft portion corresponding to the elements I Q and I l respectively.

The valve mechanism as an essential unit of every four-cycle engine isillustrated in Fig. 2, and in the preferred embodiment is characterizedin that the cam ring 6 rotates in the direction opposite to that of theimpeller 55, which also implies in the direction opposite to that of thecrankshaft since the impeller 55 is, in the embodiment shown, mounteddirectly thereon. This characteristic of the cam ring being related tothe impeller in a denite way as to the direction of rotation, althoughof no significance per se, has a distinct purpose in the engine of myinvention, which purpose when viewed from the usefulness of its results,represents a decided innovation. 'I'he effect readily recognizable isthat the valves of the engine interchange their function, the one whichnormally would be the exhaust valve becomes the intake valve, and viceversa; and this is the object apparent of the above disclosedcharacteristic. Assuming that the engine crankshaft rotates in dicatedby the arrow B in Fig. 2, then, for certain reasons revealed presently,it is desirable that the cam ring E rotate in the direction opposite tothat of the arrow B; in that case the intake valve will be the onemarked I4, and the exhaust valve will be I4'. The ulterior purpose andthe novelty of the aforementionedv feature of the cam ring l and theparticular disposition of the intake and the exhaust valves will becomeapparent when reference is taken to the divisional patent for theinduction system above cited; the curvilinear course and the angularextent and proportions of the induction ducts 26 as specified in saidpatent cover a considerable area on the engine cylinders I2 and wouldnormally interfere with the cooling of said cylinders and especiallytheir valves by obstructing the access of air thereto from the forwarddirection. Now by arranging for the intake valve to occupy that side ofthe cylinders I2 from which the induction ducts 25 approach the same,the induction ducts will assume the position substantially between twoadjacent cylinders rather than in front of them, thus leaving thecylinders themselves entirely or from the most part free for the coolingair to impinge upon. In Fig. 2, the impeller 55 rotatingcounter-clockwise, the induction ducts 26 will approach the cylinders I2from the right side, and due to the intake valve being situated on thecorresponding side as provided through the aforementioned reversal ofrotation of the cam ring 6, will conjoin said cylinders readily withoutshielding the exhaust valve I4' in particular, and without barringaccess to both of the valves for servicing. In case separate cams areemployed for the intake and the exhaust valves, or in case the impellerrotates in the dlrection opposite to that of the crankshaft, then, ofcourse, the rotation of the cam ring need necessarily not be opposite tothat of the crankshaft in order to achieve the desirable and highlyadvantageous relation between the induction ducts and the cylinders asabove, but these are `:cases involving mechanical complications whichcannot be analyzed individually in connection with the presentembodiment which is basic and typical.

'I'he reversal of rotation of the cam ring I in the particular andpreferred embodiment as illustrated, with respect to the shaft I6 andthe impeller 55 thereon is accomplished by means of an internal gear inthe cam ring drive. On the the direction inmodera shaft i6, Figs. 1 and2, is secured, as by means of the key 18, the gear I which engages theintermediate gear 2 on the stud 4; the gear 2 is integral with thepinion 3 which meshes with the internal gear 5, the gear 5 propels thecam ring 8 concentrically around the shaft I6 on the bearing 59 in adirection opposite to that of the shaft it. The cam ring 5 is providedon its circumference with cams or lobes 1 and 8 which actuate the valvesI5 and I5' respectively. The tappets it and i5' are duly spaced aboutthe Vring B for correct timing of the valves. The speed of the cam ring5 and the number of lobes thereon are, necessarily, of a definite orderand number respectively for any particular number of cylinders and for agiven direction of rotation; with the cam ring rotating opposite tothecrankshaft, as is essential for instance in the embodiment illustratedfor the particular and peculiar reasons aforementioned, the speed of thecam ring is expressed by the formula number of cylinders on one crank;and the number of lobes will be Thus in the embodiment illustrated,there being hve cylinders, the speed of the cam ring 5 will be 1A; ofthe crankshaft speed in the opposite direction, and the number of lobeswill be 2, evenly spaced.

lin the engine of my invention the cam ring drive is utilized withadvantage for other useful purposes, to Wit, for the tachometer and theoil pump drive, after the following fashion: The internal gear 5 isprovided with external teeth 9 which are in mesh with the tachometerdrive gear i supported rotatably by the boss 32 on the diaphragm 92. Theshaft 33 is journalled to the gear ill and therefrom extends into theengine crankcase and therethrough to the rear thereof Whereat it iscoupled to the tachometer drive tting 34. The gear I0 is proportionedwith respect to the gear 9 so as to readily provide the usual reductionin speed for tachometers, the standard ratio being one half of thecrankshaft speed; in the particular embodiment illustrated, the gear 9rotates with the cam ring 5 at one quarter of the crankshaft speed,therefore, by making the gear Ill one half its size, the specified speedfor the tachometer is readily obtained.

The tachometer gear I 0 engages with the oil pump drive gear Il on theshaft 42; the oil pump is shown as being, in this embodiment, of thecustomary type comprising the shafts 42 and 43 on which a pair of gears84 serves for pressure feed of oil into the engine, and another pair oflike gears 85 for scavenging oil from the sump 25. Adjacent the oil pumpis the chamber 22 which houses the oil lter screen 81. The oil lines areall incorporated in the casings of the engine, there being no exteriorconnections except those to an oil tank. Of the oil leads the mostimportant one, i. e., the pressure feed conduit 35, into-which the gears84 discharge oil, is carried through the diaphragm 92 from the oil pumpdirectly to the shaft I through the bearing 59. The pressure of the oilis controlled by means of the adjustable release valve 35 whichregulates the opening 8|,

Fig. 2, from the pressure conduit 35 into the sump 25.

The impeller 55 is driven fromvthe shaft i8 by means of the same key 16that drives the gear i.

The drive for vthe gear 53 and its mate 5I is, as for example, by meansof serrations 'I1 on the shaft I6; the gear 53 is integral with thespacing sleeve 54 which has at its forward end internal serrationscomplemental to serrations 11 on the shaft i6. The sleeve 5t has also aplurality of uni-directional cams 54 on its circumference within thestarter driving cylinder 65, which cams constitute the engaging meansfor the spring 65 on the shaft l5 through the instrumentality of thepellets 55. The serrations 11 thus serve the double purpose of rotatingthe shaft i6 by the spring 5t for starting, and for driving the gears 53and 5i from said shaft through the sleeve 54.

It will now be observed that all of the aforementioned units are, intheir particular and novel disposition in the engine of my invention,housed essentially in four principal casings including the enginecrankcase 23, the induction casing 25,-the intermediate 2B, and the endcasing 29.

The crankcase, though shown as split transversely on the cylinder centerline into two portions 33 and 2i in order to'suit a special attachmentofc-the cylinders if, can equally Well be made in one piece if any otherattachment is preferred. In this particular case the cylinders l2 areprovided with-fa beveled ange 18 by means of which they are clamped inbetween the casings 23 and 2i held together by a number of bolts 19,Fig. 2. The diaphragm 92 in the portion 2J serves primarily forsupporting the bearing 59 centrally, and secondly, for carrying thevalve tappets l5, the tachometer gear I0 and the pressure oil conduit35; 'openings 82, Fig. 2, in this diaphragm communicate between thecrankcase proper and the oil sump 25 in the portion 23.

The intermediate casing 28 is attached to the crankcase 23 by means of anumber of bolts 58 with the induction casing consisting of the ducts 28and the diaphragm 21 included between the said two former casings. Thebolts 56 pass through the ducts 2B in guide vanes 93 disposed thereintransversely between the fore and aft walls, the guide vanes thusserving, among other purposes, as spacers between the casings 23 and 28and as streamlines for the said bolts against their causing turbulencein the impeller discharge. The casing 28 furnishes the diaphragm 44 onthe forward side of the impeller 55 corresponding to the diaphragm 21 onthe rear side.

v".i'he end casing 29 together with the cover 35 is bolted directly ontothe casing 28 with the starter winding wheel 62 and the control drum 53held rotatably in the interior therebetween.

Of the units grouped on and around the crankshaft as presented in theforegoing disclosure certain ones are not absolutely essential for thefunctioning of the engine and may, therefore, in other embodiments beomitted or substituted by others; this applies particularly to theimpeller and the starter, though their inclusion in the original manneras shown can be extended with advantage to even the smallest of engineswhich it has hitherto been deemed unwarranted because of high weight andstructural difliculties. The option' of employing either magnetos or afuel pump or a generator, depending upon the working principle of theengine, has already been specified. The inclusion or the omission of thevalve mechanism is similarly subject to the type of the engine,fourcycleor two-cycle, and furthermore, in a Diesel engine the same mechanism canoperate injection pumps for the cylinders instead of or in addition tothe valves. The lm peller may be geared up instead of being mounteddirectly on the crankshaft; the starter may be substituted by any othertype, or by a reduction gearing' for the propeller. Through thesealternatives I desire to indicate what departures from the exactembodiment as described are contemplated Within the scope of the claimsappended herebelow. I claim:

l. In an engine, a central shaft having a crank at one extremity and adriving boss at the other extremity, bearing means for said shaftadjacent said extremities thereof, a pluralityof cylinders' with valves,pistons and connecting rods therein disposed substantially radiallyaround said crank, said connecting rods being journalled to said crank,avmechanism for operating said valves, an induction system for saidcylinders, an accessory drive with accessories coupled thereto, astarting means for said engine, said valve mechanism, said `inductionsystem, said accessory drive and said starting means being arrangedconsecutively on and about said shaft and between said bearing meansthereof whereby said cylinders will be spaced furthest away from saiddriving boss of said shaft.

2. In an engine, a central shaft having a crank and a driving boss attheopposite extremities thereof, bearing means for said shaft adjacentsaid extremities thereof, a crankcase housing said crank, a plurality ofcylinders with valves, pistons and connecting rods therein disposedsubstantially radially on said crankcase, said connecting rods beingjournalled to said crank therein, and a series of casings housing amechanism for operating said valves, an induction system for saidcylinders, an accessory drive, and supporting accessories to saidcylinders and said bearing means, all of said casings being arrangedadjacent one another ahead of said crankcase and between saidextremities of said shaft whereby said cylinders will be spaced furthestaway from said driving boss.

3. In an engine, a central shaft having a crank and a driving boss atthe opposite extremities thereof, bearing means for said shaft adjacentsaid extremities thereof, a crankcase housing said crank, a plurality ofcylinders with valves, pistons and connecting rods therein disposedsubstantially radially on said crankcase, said connecting rods beingjournalled to said crank therein, and a plurality of casings housing amechanism for operating said valves, an oil pump and a tachometer drive,an induction system for said cylinders, an accessory drive, a means forstarting said engine, and supporting accessories to said cylinders andsaid bearing means, all of said casings being arranged adjacent oneanother ahead of said crankcase and between said extremities of saidshaft whereby said cylinders will be spaced furthest away from saiddriving boss of said shaft.

4. In an engine, a central shaft having a crank and a driving boss atthe opposite extremities thereof, bearing means for said shaft adjacentsaid extremities thereof, a crankcase housing said crank, a plurality ofcylinders with valves, pistons and connecting rods therein disposedsubstantially radially on said crankcase, said connecting rods beingjournalled to said crank therein, a casing integral with said crankcaseon the side toward said driving boss, said casing housing mechanism foroperating said valves, a further casing adjacent said latter casinghousing an impeller and comprising a series of induction ducts extendingoutwardly to said cylinders. an intermediate casing adjacent saidimpeller casing enclosing a riser to said impeller and an accessorydrive with accessories coupled thereto. an end casing adjacent saidintermediate casing, said bearing means for said shaft being disposed insaid valve mechanism casing and in said end casing with all of said umtstherebetween whereby said cylinders will be spaced furthest away fromsaid driving boss of said shaft.

5. In an engine, a central shaft having a crank and a driving lbossatthe opposite extremiti thereof, bearing means for said shaft adjacent\said extremities thereof, a crankcase housing said crank, a pluralityof cylinders with valves, pistons and connecting rods therein disposedsubstantially radially on said crankcase, said connecting rods beingjournalled to said crank, seid crankcase comprising a tachometer driveshaft extending through the fore and aft walls thereof, and an oil pumpand an oil lter in the lowest portion thereof; a casing integral withvsaid crankcase on the side toward said driving bou, said casingenclosing a mechanism for operating said valves, for driving saidtachometer shaft and said oil pump in said crankcase, a casing adjacentsaid latter casing housing an impeller and comprising a plurality ofducts extending outwardly to said cylinders, an intermediate casingproviding the forward diaphragm for said impeller and a riser theretoand housing an accessory drive with accessories coupled thereto, an endcasing secured onto said intermediate casing and supporting a startingmeans for said engine in conjunction therewith, said bearing means forsaid shaft being disposed in said valve mechanism casing and in said endcasing with all of said units disposed therebetween whereby saidcylinders will be spaced furthest away from said driving boss of saidshaft.

6. In an engine, a crankcase, a plurality of cylinders disposed on saidcrankcase, a series of casings housing units auxiliary to said cylinderarranged consecutively ahead of said crankcase, a crankshaft extendingcentrally through said casings, and bearing means for said crankshafttherein; a mechanism in the casing next adjacent said crankcasecomprising a gear train and a spur gear concentric with said crankshaft;a shaft extending between and through the fore and aft walls of saidcrankcase, a tachometer drive fitting secured to said shaft externally,and a gear journalled to said shaft in said casing next adjacent saidcrankcase, said gear being in mesh with said spur gear therein fordriving said tachometer shaft; an oil pump in said crankcase, a shaftextending from said pump into said casing next adjacent said crankcase,and a pinion on said shaft, said pinion engaging said tachometer shaftdrive gear.

7. In an engine, a crankcase, a plurality of cylinders disposedsubstantially radially on said crankcase, intakes vales in saidcylinders, a series of casings housing units auxiliary to saidcylinders, said casings being arranged consecutively ahead of saidcrankcase, a crankshaft extending centrally through said casings, animpeller driven from said crankshaft in one of said casings, and aplurality of induction ducts extending from said impeller casingoutwardly and ansularly to said valves in the direction of rotation ofsaid impeller; a cam ring concentric with said crankshaft in another oneof said casings, and means for positively actuating said valves fromsaid cam ring; said cam ring being geared to said crankshaft in such amanner as to have a direction of rotation with respect to said impellerwhereby said intake valves Will be located on that side of saidcylinders from which the said induction ducts approach the same.

8. In an engine, a crankca'se, a plurality of cylindersA disposedsubstantially radially on said crankcase, intake and exhaust valves insaid cylinders, a series of casings housing units auxiliary to saidcylinders, said casings being arranged consecutively ahead of saidcrankcase, a crankshaft extending centrally through said casings, animpeller driven from said crankshaft in one of said casings, andinduction ducts extending from said impeller casing to said intakevalves in said cylinders, said ducts following angularly coursesconcurrent with the direction of rotation of said impeller; a cam ringconcentric with said crankshaft in another one of said casings, andmeans for positively actuating said intake and said exhaust valves fromsaid cam ring; said cam ring being geared to said crankshaft in such amanner as to have a direction of rotation opposite to that of saidimpeller whereby said intake valves will be located on that side of saidcylinders from which the said induction ducts approach angularly thesame.

9. In an engine, a crankcase, a plurality of cylinders disposedsubstantially radially on said crankcase, intake and exhaust valves insaid cylinders, a series of casings housing units auxiliary to saidcylinders, said units being arranged consecutively ahead of saidcrankcase, a crankshaft extending centrally through said casings, animpeller mounted on said crankshaft in one of said casings, andinduction ducts extending from said impeller casing to said intakevalves in said cylinders, said ducts following angularly coursesconcurrent with the direction of rotation of said impeller and saidcrankshaft; a cam ring concentric with said crankshaft in another one ofsaid casings, and means for positively actuating said intake and saidexhaust valves from said cam ring; said cam ring being geared to saidcrankshaft in such a manner as to have a direction of rotation oppositeto that of said impeller thereon whereby said intake valves will belocated on that side of the said cylinders from which the said inductionducts approach angularly the same.

JAN PAVLECKA.

